A state-of-the-art gas chromatograph-mass spectrometer-data system is requested to be used principally by four core users (75%) in the Departments of Pharmacology, Medicine and Chemistry. The four areas of core research include fragmentation studies of biochemicals, chemistry of natural products, drug metabolism, and investigations of the physiological role and metabolic fate of prostaglandins. In addition this instrumentation will help meet the analytical nedds of more than 15 other researchers (25% usage) in the geographic area. None of the existing mass spectometers at Vanderbilt can provide all of the requirements of resolution and mass range up to m/z 1000 as well as sensitivity into the femtogram range that are necessary for proper conduct of the core research. In addition to these fundamental features, the new instrumentation is designed for negative ion detection during chemical ionization and for complete analyses of metastable ion transitions. All of these instrumental features will catalyze a variety of research projects and career development of several investigators whose productivity is currently limited by out-of-date GC/MS instrumentation.